Deciphering the nitric oxide to carbon monoxide lung transfer ratio: physiological implications

Using simultaneous nitric oxide and carbon monoxide lung transfer measurements (T(LNO) and T(LCO)), the membrane transfer capacity (D(m)) and capillary lung volume (V(c)) as well as the dimensionless ratio T(LNO)/T(LCO) can be calculated. The significance of this ratio is yet unclear. Theoretically, the T(LNO)/T(LCO) ratio should be inversely related to the product of both lung alveolar capillary membrane (mu) and blood sheet thicknesses (K). NO and CO transfers were measured in healthy subjects in various conditions likely to be associated with changes in K and/or mu. Experimentally, deflation of the lung from 7.4 to 4.8 l decreased the T(LNO)/T(LCO) ratio from 4.9 to 4.2 (n=25) which was consistent mainly with a thickening of the blood sheet. Compared with continuous negative pressure breathing, continuous positive pressure breathing increased this ratio suggesting a thinning of the capillary sheet. It was also observed with 12 healthy subjects that slight haemodilution that may thicken the blood sheet decreased the T(LNO)/T(LCO) ratio from 4.85 to 4.52. In conclusion, the T(LNO)/T(LCO) ratio is related to the thickness of the alveolar blood barrier. This ratio provides novel information for the analysis of the diffusion properties.

Photodegradation and in vitro phototoxicity of aceclofenac

Aceclofenac (Airtal) (1) is a photoallergic and phototoxic anti-inflammatory and analgesic agent. This drug is photolabile under aerobic and anaerobic conditions. Irradiation of an ethanol-solution of aceclofenac under oxygen or argon at 290-320 nm affords via decarboxlation compound 2 as the main isolated and spectroscopically identified photoproduct, besides hydroxylamine derivates 3 and 4. A radical intermediate was evidenced spectrophotometrically with GSH and DTNB, as well as by the dimerization of cysteine. Red blood cell lysis photosensitized by 1-4 was investigated. Furthermore, in a lipid-photoperoxidation test with linoleic acid the in vitro phototoxicity of aceclofenac was also verified. The photoinduced generation of peroxide by compound 1 was determined during the irradiation in presence of NADPH by chemiluminescence. In relation to the photoallergic activity of this drug, the interaction of aceclofenac with human serum albumin (HSA) has been studied through fluorescence spectroscopy. No photoinduced binding was observed after irradiation of compounds 1 in the presence of human serum albumin.

Évolution de la capacité inspiratoire au cours de la BPCO décompensée

INTRODUCTION

Inspiratory Capacity (IC), which reflects dynamic pulmonary hyperinflation, correlates with outcome in moderate exacerbation of COPD. Whether this is also true in COPD with acute respiratory failure (ARF) has not been studied.

METHODS

A prospective multicenter assessment of IC measurement feasibility, reliability, time-course and relationship to outcome in COPD with ARF was conducted. Dyspnea (visual analogue scale) and IC were repeatedly measured. Outcome was classified as not favourable (death or intubation or non invasive ventilation increased or patient referred to ICU from respiratory ward) or favourable (none of the above criteria).

RESULTS

Fifty patients were included and 48 analysed. IC measurement was possible in all but one patient and its coefficient of variation was 9+/-8%. Between inclusion into the study and discharge, IC increased from 39.9+/-15.5 to 50.2+/-14.5% pred (p<0.001) and dyspnea declined from 48+/-23 to 33+/-22 mm (p<0.001). Inclusion IC was not different on average between patients with or without favourable outcome.

CONCLUSION

In COPD patients with ARF, IC measurement at bedside was feasible and reproducible. IC was low at entry and increased over time from inclusion to discharge tending to correlate with patient outcome.

Isolation and comparative analysis of the wheat TaPT2 promoter: identification in silico of new putative regulatory motifs conserved between monocots and dicots

Phosphorus deficiency is one of the major nutrient stresses affecting plant growth. Plants respond to phosphate (Pi) deficiency through multiple strategies, including the synthesis of high-affinity Pi transporters. In this study, the expression pattern of one putative wheat high-affinity phosphate transporter, TaPT2, was examined in roots and leaves under Pi-deficient conditions. TaPT2 transcript levels increased in roots of Pi-starved plants. A 579 bp fragment of the TaPT2 promoter is sufficient to drive the expression of the GUS reporter gene specifically in roots of Pi-deprived wheat. This TaPT2 promoter fragment was also able to drive expression of the GUS reporter gene in transgenic Arabidopsis thaliana, under similar growth conditions. Conserved regions and candidate regulatory motifs were detected by comparing this promoter with Pi transporter promoters from barley, rice, and Arabidopsis. Altogether, these results indicate that there are conserved cis-acting elements and trans-acting factors that enable the TaPT2 promoter to be regulated in a tissue-specific and Pi-dependent fashion in both monocots and dicots.

Effect of Statin Treatment on Oxidative Stress and Renal Function in Renal Transplantation

The beneficial action of statins on the lipid profile, cardiovascular disease, and death is well known. Besides their lipid-lowering role, these drugs have pleiotropic action that derive from their prevention of the synthesis of isoprenoids, mediators in cell signaling. Thus, due to their antioxidant capacity, statins can decrease the production of reactive oxygen species by inhibiting NAD(P)H oxidase activity. Previous studies by our group have described increased oxidative stress status in renal transplantation that might benefit from HMG CoA reductase inhibitor therapy. The aim of this study was to assess the influence of statins on stress parameters and their relevance to renal function in kidney transplantation. In 58 transplanted patients a first blood sample was obtained, without statins followed by 21 patients treated with statins (group 1) and 37 patients without drug (group 0) for a 6-month study period. We collected clinical data as well biochemical results on lipid profile, creatinine and oxidative stress. Lipid profile reduction was significant among group 1 compared with group 0. An increased glutathione peroxidase (GPx) among observed in all patients was greater in the statin-treated group (P = .006). No differences in creatinine or Cockroft-Gault values were observed between before versus after drug administration. In conclusion, statin treatment in renal transplantation improves the lipid profile and may increase GPx-measured antioxidant capacity but appears to have no short-term effect on renal function.

Determinación de cortisol salival en el diagnóstico de la enfermedad de Cushing pediátrico

Endogenous Cushing's syndrome in children is a very rare entity. Diagnosis is complex due to the wide variety of tests available. Recently, the utility of salivary cortisol has been proposed for the diagnosis of this entity, although greater evidence is required, especially in pediatric patients. We report a 14-year-old girl with Cushing's disease due to a pituitary microadenoma in whom salivary cortisol determination was very useful for the diagnosis.

Influence of thyroid disorders on kidney angiotensinase activity

Thyroid disorders affect renal function, which involves changes in local renin angiotensin system (RAS). Angiotensin peptide levels in the tissue are regulated by the activity of several aminopeptidases (AP) known as angiotensinases. The nature and consequences of the thyroid-induced RAS changes are not completely understood. We investigated the relationship between thyroid status (hyper- and hypothyroidism) and several kidney AP actions involved in RAS control. We have determined fluorometrically soluble (SOL) and membrane-bound (M-B) alanylaminopeptidase (AlaAP), glutamylaminopeptidase (GluAP) and aspartylaminopeptidase (AspAP) activity using naphthylamide derivatives as substrates. Sprague-Dawley rats were divided into three groups--control, hyperthyroid, and hypothyroid. Hyperthyroidism was induced by daily subcutaneous injection of L-thyroxin (300 microg/kg/day). Hypothyroidism was induced by continuous administration of methimazole (0.03%) in drinking water. Hypothyroid animals demonstrated a significant increase in SOL and M-B GluAP activity in renal cortex and a decrease in M-B AlaAP compared to euthyroid rats. This result may suggest higher Ang III availability. In hyperthyroid animals, M-B AlaAP and M-B AspAP activity increased significantly, which may suggest increased Ang III to Ang IV metabolism and greater formation of Ang 2-10, respectively. In contrast, no differences were observed between euthyroid and hypothyroid animals for SOL and M-B AP activity in renal medulla. However, hyperthyroid animals demonstrated a significant decrease in SOL and M-B GluAP activity compared to euthyroid rats, which may suggest a greater availability of Ang II in renal medulla. Alterations in angiotensin metabolism may, in part, account for some changes in renal function during thyroid disorders.

Approaches to Scrapie diagnosis by applying immunohistochemistry and rapid tests on central nervous and lymphoreticular systems

Comparative studies evaluating the performance of Transmissible Spongiform Encephalopathies (TSE) rapid tests (validated for Bovine Spongiform Encephalopathy samples) on Scrapie samples have not been reported widely, particularly those dealing with lymphoreticular system tissues to a much lesser extent. The main objective of this study was to compare the ability of two current rapid tests (Western blot and Luminiscence Immunoassay Prionics-Check; WB and LIA, respectively) to detect PrPsc using central nervous system as well as lymphoreticular system samples corresponding to naturally infected animals. Thirty-four Scrapie-affected sheep, 26 with clinical signs of the disease, were included in the study. Tonsil, retropharyngeal lymph node and medulla oblongata were assessed by three tests: immunohistochemistry (confirmatory test), WB and LIA (rapid tests). The conclusion which can be drawn from this study is the fact that all animals involved in the study, including those at a preclinical stage, could be diagnosed regardless of the test used (with immunohistochemistry consistently showing higher sensitivity) only when the analyses of both the central nervous system and the lymphoreticular system were considered. The choice of these tissues for routine diagnosis is, therefore, proposed as a valuable tool to highly reduce the number of undetected positive cases.

Clozapine prevents apoptosis and enhances receptor-dependent respiratory burst in human neutrophils

The present study was undertaken to determine if the antipsychotic drug clozapine (CLZ) in the concentration range 2-50 microM can rescue polymorphonuclear cells (PMNs) from undergoing apoptosis. Our results indicate that 20 microM CLZ can rescue PMNs both from UVB-accelerated (28.0% vs. 45.9% for control without CLZ; P < 0.05) and from spontaneous (35.8% vs. 57.6%; P < 0.05) apoptosis whereas 50 microM CLZ could rescue PMNs from spontaneous (34.3% vs. 57.6%; P < 0.05) apoptosis only. Furthermore, since apoptosis has been reported to involve the impairment of PMN function, we evaluated the effects of CLZ on respiratory burst in UVB-irradiated and in unirradiated PMNs. When 20 or 50 microM CLZ-pretreated PMNs were aged in a culture during 4 h, the luminol-dependent chemiluminescence (CL) response was 3-fold (P < 0.01) and 2.5-fold (P < 0.05) increased, respectively, by subsequent exposure to serum opsonized zymosan (OZ). When 50 microM-pretreated PMNs were either UVB-irradiated or unirradiated, the CL response was 2.6-fold (P < 0.05) and 3.3-fold (P < 0.05) increased, respectively, after subsequent exposure to formyl-methionyl-leucyl-phenylalanine (fMLP). In contrast, the degree of enhancement was negligible upon subsequent exposure to ionomycin or phorbol myristate acetate (PMA). When incubation times were extended up to 22 h, the CL response induced by OZ in 20 microM CLZ-treated PMNs had a 4.9-fold increase (P < 0.001). This priming effect could be reverted when 20 microM CLZ-treated PMNs (aged 4 h in culture) were coincubated for 5 min with the protein tyrosine kinase inhibitor genistein as well as with the phosphatidylinositol 3-kinase (PI3-K) inhibitor wortmannin. These findings suggest that CLZ primes respiratory burst and prevents PMN apoptosis as a consequence of tyrosine phosphorylation- and PI3-K activation-dependent signal transduction pathways.

Controlled clinical trial of IV cyclophosphamide versus IV methylprednisolone in severe neurological manifestations in systemic lupus erythematosus

BACKGROUND

Severe neurological involvement in systemic lupus erythematosus (NPSLE) is one of the most dreadful complications of the disease.

OBJECTIVE

To identify the best drug, dose, and treatment.

PATIENTS AND METHODS

The study was a controlled clinical trial at two tertiary care centres of patients with SLE according to the ACR criteria, with incident (no more than 15 days) onset of severe NP manifestations such as seizures, optic neuritis, peripheral or cranial neuropathy, coma, brainstem disease, or transverse myelitis. Induction treatment with 3 g of IV methylprednisolone (MP) followed by either IV monthly cyclophosphamide (Cy) versus IV MP bimonthly every 4 months for 1 year and then IV Cy or IV MP every 3 months for another year. The primary end point was response to treatment: at least 20% improvement from basal conditions on clinical, laboratory, or specific neurological testing variables.

RESULTS

Overall, a response rate of 75% was observed. Of the 32 patients studied, 18/19 receiving Cy and 7/13 receiving MP responded to treatment (p<0.03).

CONCLUSIONS

Cy seems to be more effective than MP in the treatment of acute, severe NPSLE.

Modulation Factors of Oxidative Status in Stable Renal Transplantation

Reactive oxygen species (ROS) trigger a biomolecular alteration that causes functional and structural changes. In renal transplantation, there is an increase in oxidative phenomena related to endothelial dysfunction, inflammation, and atherosclerosis, the main cause of cardiovascular complications and chronic allograft failure. The present study was designed to assess the oxidative state of transplant patients with stable renal function, in order to establish differences in oxidative, biochemical, and clinical parameters between patients treated with tacrolimus versus cyclosporine. We studied 67 stable kidney transplant patients treated with calcineurin inhibitors who were not receiving cholesterol-lowering therapy, and 14 healthy subjects. Data were collected on biochemical parameters: lipid profile (apoA, apoB, total cholesterol and fractions, and triglycerides); urea; and creatinine; oxidative parameters: malondialdehyde (MDA) as a lipid peroxidation marker, glutathione peroxidase (GPx), catalase, superoxide dismutase (SOD), glutathione reductase (GR), and antibodies against oxidized LDL; and clinical variables. Transplanted patients showed a higher oxidative status (MDA increase and GPx decrease) than healthy subjects. The oxidative status did not differ between the cyclosporine and tacrolimus cohorts. Some factors during the posttransplant period, such as delayed graft function, cytomegalovirus infection, and microalbuminuria, which may damage renal function, produce a decreased antioxidant capacity (lower GPx).

Role of neuronal nitric oxide synthase in response to hypertonic saline loading in rats

AIMS

This study analyses the influence of neuronal nitric oxide synthase (nNOS) blockade with 7-nitroindazole (7NI) on the haemodynamic and renal response to a hypertonic saline load (HSL). We also evaluated the effects of non-specific NOS inhibitor Nomega-nitro-L-arginine methyl ester (L-NAME).

METHODS

The following groups were used: controls, rats treated with 7NI at 0.5 or 5 mg kg(-1), and rats treated with L-NAME at 0.5 or 5 mg kg(-1). A further five groups received an isotonic saline load (ISL).

RESULTS

Mean arterial pressure (MAP) was significantly increased in control rats after HSL. MAP was further increased in both 7NI-treated groups, and the L-NAME groups showed marked dose-related pressor responses. During ISL, MAP was only significantly increased in the group treated with 5 mg kg(-1) of L-NAME. The pressure-natriuresis relationship during the experimental period after the HSL was reduced in the 7NI group treated with 5 mg kg(-1) and severely attenuated in both L-NAME groups. The increase in plasma sodium was significantly greater after the HSL in both 7NI groups and both L-NAME groups compared with controls.

CONCLUSIONS

The present results suggest that nNOS and other NOS isozymes play a counter-regulatory role in the pressor response to HSL. Moreover, the blockade of nNOS with the higher dose of 7NI produces a blunted pressure-natriuresis relationship in response to the HSL. Finally, it is concluded that nNOS participates in the homeostatic cardiovascular and renal response to hypertonic saline loading by attenuating the blood pressure increase and hypernatremia, and facilitating natriuresis.

Vaginal misoprostol 800 μg every 12 h for second-trimester abortion

The objective of the study was to evaluate the efficacy and safety of 800 microg misoprostol every 12 h, up to three doses, for pharmacological second-trimester abortion. The misoprostol doses were always administered by doctors into the vagina. Two-hundred and sixty-nine women with gestations within 12 and 20 weeks were recruited into the study. The main outcomes measured were successful abortion (passage of fetus and placenta without surgery), side effects and mean drop in hemoglobin, vaginal bleeding and mean time of return of menstruation. Complete abortion occurred in 245/269 (91.1%, 95% confidence interval 87-94%) patients. Vaginal bleeding lasted 15.7 +/- 4.1 days. The mean drop in hemoglobin, calculated 24 h after abortion, were statistically significant (p = 0.0001), as also was the mean hemoglobin measured 14 days after abortion, but without clinical relevance. According to the results obtained, 800 microg of misoprostol administered every 12 h, up to a maximum of three doses, could be a valid method for abortion within 12 and 20 weeks of gestation.

Predictive factors of intensive care unit admission in patients with haematological malignancies and pneumonia

OBJECTIVE

To describe early signs at the onset of pneumonia occurring in the haematology ward which could be associated with a transfer to the ICU.

DESIGN

A 13-month preliminary prospective observational cohort study.

SETTING

Department of haematology and (32-bed) medical intensive care unit (ICU).

PATIENTS

Fifty-three of 302 patients hospitalised in the haematology ward who developed presumptive clinical evidence of pneumonia were enrolled.

MEASUREMENTS AND RESULTS

At the onset of the clinical evidence of pneumonia (day 1), we compared variables between patients requiring an ICU admission and those who did not. Twenty-four patients (45%) required a transfer to the ICU. Factors associated with ICU admission were: numbers of involved quadrants: 2.3 vs 1, P=0.001 and oxygenation parameters (initial level of O(2) supplementation: 3.5 vs 0.9 l/min, P<0.05), the presence of hepatic failure (58% vs 10%, P<0.01), Gram-negative bacilli isolated in blood culture (7 vs 1, P=0.01). In the multivariate analysis, a decrease of 10% in the SaO(2) and the requirement of nasal supplementary O(2) at the onset of acute respiratory failure increased the risk of admission to MICU, respectively, by 18 and by 14. The overall 6-month mortality rate of the 53 patients was 28%.

CONCLUSION

Parameters of oxygenation and radiological score could be associated with this transfer on day 1 of the onset of pneumonia occurrence. A further study should evaluate an earlier selection of this type of patient, followed by an "early" admission to the MICU, in order to improve ICU outcome.

Effects of deoxycorticosterone on renal vascular reactivity and flow-pressure curve in spontaneously hypertensive rats

The role of mineralocorticoids as sodium retaining hormones has been recently enlarged to include their function as modulators of cardiovascular function and injury. This study evaluated the contribution of possible functional changes in resistance vessels to the additional BP increase produced by the chronic administration of DOCA to SHR. The flow-pressure curve and renal responses to vasoconstrictors (phenylephrine [Phe] and angiotensin II [AII]) and vasodilators (acetylcholine [ACh] and nitroprusside [NP]) were characterized in isolated kidneys from Wistar Kyoto (WKY) and SHR treated or untreated with DOCA for nine weeks. DOCA increased BP in SHR but did not modify BP in WKY rats. Kidneys from SHR showed enhanced reactivity to Phe and AII that was not increased by DOCA. DOCA reduced sensitivity to AII in SHR. Responsiveness to ACh was increased in SHR and was not attenuated by DOCA in WKY or SHR. Vasodilator response to NP was not significantly affected by DOCA in WKY or SHR. The flow-pressure curve was markedly up-shifted in SHR when compared with kidneys from WKY rats. DOCA administration did not modify the flow-pressure curve in WKY but produced attenuation at low flow levels in SHR. Our results demonstrate that DOCA increases BP in SHR but does not increase the flow-pressure curve or renal vascular reactivity to vasoconstrictors, and does not reduce responsiveness to endothelium-dependent and independent vasodilators in SHR or WKY rats. Therefore, our data suggest that the BP increase produced by DOCA in SHR is not related to abnormalities in vascular function in resistance vessels.

Antioxidant properties of dipyridamole as assessed by chemiluminescence

The ability of dipyridamole (DIP) to scavenge oxygen metabolites generated by either activated human neutrophils (PMNs) or cell-free systems using luminol(s)- and lucigenin-enhanced chemiluminescence was investigated. In the presence of DIP (15-50 microM) a dose-dependent inhibition period was seen in phorbol myristate acetate (PMA)-stimulated PMNs as assayed by isoluminol-enhanced chemiluminescence (ILCL) with horseradish peroxidase (HRP). Although such a lag period was not observed in the absence of HRP, 50 microM DIP inhibited extracellular ILCL by more than 50%. Intracellular luminol-enhanced chemiluminescence (LCL) as assayed in either PMA- or in ionomycin-activated PMNs was not affected by dipyridamole (15-50 microM). In cell-free systems, DIP produced concentration-dependent inhibition in H2O2-(45% at 50 microM), OH- (40%, at 0.1 microM) and HOCl-(20% at 10 microM). Both absorbance and fluorescence scans revealed that DIP is able to react with equimolar quantities of either H202 or HOCl. These results suggest that DIP scavenges reactive oxygen species (ROS) presumably secreted by activated human PMNs in the following decreasing order: *OH > HOCl > H2O2 >> O2-.